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Frontlines

Not for the Squeamish
The humble earthworm may hold the key to removing one of our most deadly environmental toxins: PCBs.

Photo of an earthworm Charles Darwin admired the earthworm extravagantly. "It may be doubted," he wrote in 1881, "if there are any other animals which have played such an important part in the history of the world as these lowly organized creatures." The earthworm is a natural organic chemist, cultivator, and fertilizer. But it may have yet another talent, one that Darwin would never have discovered: toxic cleanup specialist. It turns out that PCBs -- among the nastiest of modern pollutants -- may be no match for the humble earthworm.

In addition to their toxicity (the Environmental Protection Agency has designated them a probable human carcinogen), polychlorinated biphenyls are notorious for two reasons. First, they "bioaccumulate." In other words, their concentration in tissue increases dramatically as they move up the food chain. Second, they are virtually indestructible.

For half a century, until their use was banned in 1979, PCBs were regarded as a miracle of the industrial age. With their stability, low volatility, and extreme fire resistance, they made wonderful insulators for electrical transformers and capacitors. Their largest user was General Electric, whose plants in New York State and Pittsfield, Massachusetts, discharged massive amounts of PCBs into the Hudson and Housatonic rivers. A series of consent decrees in the 1990s obliged G.E. to spend hundreds of millions of dollars to clean up the mess it had left behind. But the settlements left a large question unanswered: How was this to be accomplished?

There are two basic alternatives for disposing of PCBs. One is incineration, the other dumping in hazardous-waste landfills. Both methods are expensive and controversial. At the G.E. facility in Pittsfield, for example, one of the largest landfills used for PCB-contaminated soil is Hill 78, which looms high above the Allendale Elementary School.

Tim Gray, who was trained as a chemist and biologist before becoming executive director of the Housatonic River Initiative, has been battling G.E. for years. Sites like Hill 78 keep him awake at night.

So when Gray learned of the work of a Slovak scientist named Oto Sova, he was excited. Sova was using the Californian earthworm, Eisenia foetida -- or ground-up earthworm enzymes, to be precise, in a solution called Enzymmix -- to remediate soils contaminated with petroleum derivatives or, most ambitiously, toxins such as phenols, cresols, DDT, and even PCBs. Better yet, Enzymmix promised to work in situ, either by being sprayed directly on contaminated surfaces or by being injected into the ground through plastic tubes.

Sova's remedy has been successfully tested at gas stations, on airport runways, and at other contaminated sites in five European countries. "I didn't know if this was for real or if it was too good to be true," Gray says. So he went to Europe to observe the enzymes in action. He was impressed enough with what he saw to take soil samples from G.E.'s Pittsfield site to be tested at the State University of New York at Albany and at HydroTechnologies, a private environmental laboratory in New Milford, Connecticut.

HydroTechnologies' lab director, Lawrence Paetsch, tested two different soil samples, with PCB levels of 250 and 450 parts per million (ppm) respectively. (The EPA considers anything above 50 ppm to be hazardous.) Paetsch says that a single application of the enzymes "showed a significant reduction in PCB concentration: On average, 62 percent of the original PCB content was removed." A second round of tests showed 76 percent removal.

If Sova's earthworm cocktail is to be approved for use in the United States, the next step is for it to be tested by the EPA's Superfund Innovative Technologies Evaluation Program (SITE). Tim Gray is optimistic. "When I went to Europe," he says, "I was about 1 percent convinced. Now I'd say I'm 80 percent there."


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The Human Animal
The Suburban Pilgrim
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Killing 'Em Softly
It's time to throw out those roach traps.

Photo of a cockroach Cockroaches. A recent survey ranked them as the most despised creatures on earth. They're also a known health risk. Allergens from their feces, saliva, and body parts are a common trigger for asthma attacks, particularly among inner-city children. So it's understandable if you've turned a blind eye to the nasty chemicals traditionally used to zap the loathsome pests.

Fortunately, a variety of nontoxic options are now available. Environmentally friendly pest-control services have in recent years proliferated like, well, cockroaches. They are a far cry from old-fashioned exterminators, who spray foul-smelling chemicals in obvious locations -- along the edge of the bathtub, near the garbage pail -- where roach traffic is heavy, but where small children and pets are also easily exposed.

The new "integrated pest management contractors" take a different approach: They use no poison. First, they seal up potential entranceways such as cracks in the walls or the space underneath a front door. Then they attract the creepy crawlers with a sucrose-based bait. The bait isn't fatal; instead, it shuts down the roach's reproductive abilities, ridding your home of offspring for months at a time. And it's not harmful to humans. According to Jeff Eisenberg of Pest Away Exterminators, in New York City, you could eat a container of the bait without any health problems (not that he'd exactly recommend it).

While you're looking for a green exterminator in your area, try to hold off on remedies such as Combat, which contains the chemical hydramethylnon, a possible human carcinogen. And whatever you do, don't use that old can of Raid that's been sitting underneath the kitchen sink for years. Until 2000, its active ingredient was the nerve gas derivative Dursban, which the EPA has since outlawed.
-- Joel Gershon

For more information on pesticides: www.epa.gov/pesticides/
controlling/doanddont.htm





Photos: left, Earthworm Research Group; right, João Freitas

OnEarth. Spring 2005
Copyright 2005 by the Natural Resources Defense Council